A glycoprotein of oviductal origin alters biochemical properties of the zona pellucida of hamster egg

Eggs were isolated from ovaries and oviducts of the golden hamster and the components of zonae pellucidae were examined using density gradient SDS‐polyacrylamide electrophoresis. Zonae of ovarian eggs (ZP‐OVA) had three major components corresponding to the so‐called ZP‐1, ZP‐2, and ZP‐3. Zonae of recently ovulated eggs collected from oviducts (ZP‐OVI) had a 200–240 K component (ZP‐O) in addition to the three components present in ZP‐OVA. When ovarian and oviductal eggs were stained with FITC‐conjugated B. simplicifolia‐1 lectin (BS‐1), which specifically binds to alpha‐D‐galactose‐ or alpha‐N‐acetyl‐D‐galactosamine‐like terminal saccharide residues, ZP‐OVI was intensely stained, while ZP‐OVA was not. ZP‐OVA gained the ability to bind to BS‐1 after a brief treatment with oviduct extracts. These results suggest that biochemical properties of hamster zonae change after transport of eggs from ovary to the oviduct. The addition of the 200–240 K component of oviductal origin to preexisting zona components seems to be responsible for this change.